There is some disagreement among various traditional sources over whether
the Sahasrara chakra or "thousand petaled lotus" is located at the crown
point at the very top of the head, or at a distance above the head.
I have followed Shyam Sundar Goswami and Sri
Aurobindo in locating it above the head, as oposed to
Sir John Woodroffe (Arthuur Avalon) and the Theosophist C. W. Leadbeater
who place it at the top of the head.

50 in number in each layer: Ang to L(rh)ang or Kshang,
arranged from right to left

colour

petal-colour, or normal colour

Pericarp colour

golden

In the pericarp

(see diagram below)

the circular moon-region
the luminous triangle (inside the moon-region)
ama-kala (inside the triangle)
ama-kala is subtle, shining in colour and crescent-shaped (in one-half
coil)
nirvana-kala (inside ama-kala)
nirvana-kala is very subtle, shining red in colour, and crescent-shaped (in one-half
coil)
nirodhika-fire (within nirvana-kala)
nirvana shakti (inside nirvana-kala)
nirvana shakti is extremely subtle, and shining red in colour
void (inside the triangle)
void is in the form of a circle and is the centre of Supreme Bindu
Visarga; its first point is just beyond ama-kala, and the second point
is just below Supreme Bindu
Divine Sharikhini who is above the second point of Visarga, and extends
from Supreme Bindu, passing through Supreme Nada, Shakti principle to Sakala
Shiva in coils, and then is absorbed into Parama Shiva [the Absolute]

Further Associations

The majority opinion seems to be that above the Crown
or Nirvana Chakra are not one but several higher centres, which, like
the inner mid-line centres, are not a part of the regular microcosmic orbit.
Sri
Aurobindo mentions only one, the Sahasrara. Shyam Sundar
Goswami [Laya Yoga] refers to two: the Guru Chakra, white in colour
and possessing twelve petals, and the Sahasrara or Sahsradala Chakra, with
a thousand petals, of golden or variable colour. In the Radha
Soami system however there are five higher chakras, the first
being the Crown or Sahasrara centre, and each corresponding to a particular
heaven region and inner or yogic sound (nada or shabda). Ann
Ree Colton speaks of five chakras above the Crown centre.
Whatever the number, all agree that these higher chakras represent varying
degrees of transpersonal or higher spiritual Intuitive Divine Consciousness.
Barbara
Brennan refers to the highest point in this central chakra line
the ID point or individuation point; located about a metre above the head,
it represents our first individuation out of the void or unmanifest Godhead
[Light Emerging, p.289]. This would be the same as Ann Ree
Colton's "Eternal Sustaining Atom" or "Atma" located above the head as
far as the arms can reach, and which constitutes the highest sphere of
spiritual consciousness. This is region of the superconscious principle
and demiurgic hierarchies [Colton, The Third Music, pp.85-6, 124, 132].

The 1000 petals of the Sahasrara, arranged in 20 layers,
each containing 50 petalsand the arrangement of the petals giving (as a cross-section?)
a bell-shaped appearance